You can get these games on GOG Connect, if you own them on Steam:
More information.BAPHOMETS FLUCH II: DIE SPIEGEL DER FINSTERNIS
BROKEN SWORD: DIRECTOR'S CUT
EADOR: GENESIS
FROZEN SYNAPSE
METRO 2033 REDUX
WITCHER: ENHANCED EDITION, THE
WITCHER 2: ASSASSINS OF KINGS, THE - ENHANCED EDITION
VANGERS
ALIEN SHOOTER + EXPANSIONS
FROZEN CORTEX
HUNIEPOP
MOTO RACER
MOTO RACER 2
MOTO RACER 3 GOLD EDITION
RISK OF RAIN
SINS OF A SOLAR EMPIRE®: REBELLION ULTIMATE EDITION
STARBOUND
WITCHER ADVENTURE GAME, THE
WORMS WORLD PARTY REMASTERED
ZOMBIE SHOOTER